• In our Delayed Coker unit Furnace, Plate type APH supplied by GEA Eco flex India Pvt Ltd is installed. Since last few months we are unable to increase Induced draft fan suction temperature as per our process requirement (To maintain acid dew point delta). Keeping in view of not increasing suction temperature we suspecting this furnace Combustion air APH may be leak and during furnace pigging/shutdown opportunity we thoroughly checked this APH but couldn’t find the leak If anyone having experience/expertise in above described matters, kindly share with us (like how to identify leak in furnace APH and what is standard practice follow to arrest the leak) Your valuable response will be appreciated!



  • tariq malik, CITGO, corpus6906@yahoo.com

    One could check the O2 content of the flue gases as they exist the furnace and around the APH. Check for any ambient air bypassing the APH (not your issue) and the draft to the I.D. fan.



  • Nagarathinam S Murthy, McKinsey & Company, Chennai, nssvdvr@gmail.com

    Typically one provides Steam Coil Air Preheater (SCAPH) before cold air Vs hot flue gas to control / manipulate acid dew point. If not provided, pl get one installed and allow cold air to be heated to say 60 deg C prior to Flue Gas Vs Air heater. Look at material of construction of flue gas path and make changes for lasting & reliable operation while stretching the limit of dew point margin. Use sulphur free fuel (mostly Fuel gas fired is preferred) which is good for Coker process too to maintain uniform heat flux in radiation coils.



  • Joseph Gentry, GTC Vorro Technology, jgentry@gtcvorro.com

    I suggest a solution pathway which is to challenge the requirement for acid gas dewpoint delta. If you remove all of the sulphur components from the fuel gas, this restriction can be eliminated. Solutions from the SweetTreat family of GTC Vorro Technology can help.